A universal goal in the production of luggage is a case which is lightweight, durable and inexpensively manufactured. Achievement of all three of these objectives has proved to be elusive. One approach has been to provide a unitary one-piece plastic frame which supports the fabric of a soft-sided luggage case. Properly constructed, such a case can be reasonable durable and of relatively light weight. However, the cost of manufacture is undesirably quite high. This is because the one-piece plastic frame requires a large and expensive mold so that the cost of tooling becomes sizeable. Moreover, each size of case requires its own set of tooling. The mold to produce one frame cannot be used to produce a frame of any other size. Tooling for an entire luggage collection, therefore, becomes excessively costly and can be justified only when extremely high production volume can be achieved. Even so, the cost of tooling remains a factor of expense. Inventory requirements inherently are high, and the frames are bulky so as to require large storage capacity prior to assembly into completed luggage.
A segmented frame for soft-sided luggage is disclosed in U.S. Pat. No. 3,592,314, but this has several drawbacks. It is adapted for production out of metal and so is relatively heavy. It is also costly. A metal frame normally cannot be bent and distorted under service conditions and have the memory to return to its original contour when the stress on it is removed. Hence, it will not possess the durability of a frame constructed out of an appropriate plastic. The frame of this patent provides narrow corner pieces which do not extend the full width of the case at its corners and so do not offer full support across the width of the case at the corners. Also, the fabric covering is exposed at the corners so as to be subject to wear and damage.